TEHRAN (AFP) — An Iranian airliner en route to neighbouring Armenia crashed into farmland northwest of Tehran on Wednesday, and all 168 people on board are feared dead, officials and local media reported.

Witnesses said the plane exploded after it dropped of out of the sky, and television images showed a vast crater at the disaster site littered with debris of plane parts, shoes and clothes.

State television's website said all aboard were "most probably were dead."

The Caspian Airlines plane crashed near a village outside the city of Qazvin shortly after takeoff from Tehran's international Imam Khomeini airport.

"The aircraft all of a sudden fell out of the sky and exploded on impact, where you see the crater," a witness told Iran's English-language Press TV from the crash site near the village of Janat Abad.

Iran, which has been under years of international sanctions, has suffered a number of aviation disasters over the past decade.

Civil aviation spokesman Reza Jafarzadeh said 153 passengers and 15 crew members were on board the airliner, which took off for the Armenian capital Yerevan at 11:33 am (0703 GMT).

"The plane took off from the Imam Khomeini airport and 16 minutes later it disappeared off the radar and then it crashed," he said.

"We can not confirm anything more before we receive additional information from the team that we despatched at the crash site."

Press TV said the plane was believed to be a Russian-built Tupolev.

"The passenger plane was completed destroyed and the wreckage was scattered everywhere," the state news agency IRNA quoted Qazvin police chief Masoud Jafari Nasab as saying.

"Most probably all passengers on board have been killed in the crash."

Ahmad Mousavi, secretary general of the Iranian Red Crescent, said: "The massive explosion caused severe burns. We were unable to do anything."

Twenty-nine people were killed in September 2006 when an airliner came off the runway after landing in the eastern city of Mashhad and burst into flames.

In November of that year, an Iranian military plane crashed on takeoff at Tehran's Mehrabad airport, killing all 39 people on board, including 30 members of the elite Revolutionary Guards force.

Iran's civil and military fleet is made up of ancient aircraft in very poor condition due to their age and lack of maintenance. The Iranian regime is barred by sanctions from buying American Boeing planes or European Airbus aircraft when they include a significant number of US parts.

Caspian Airlines was established in 1992 in Tehran.

Its website said it operates more than 50 regular and numerous charter flights each week between Iranian cities and international flights to Hungary, the United Arab Emirates, Syria, Ukraine, Armenia, Belarus and Turkey.

Landlocked Armenia has been seeking closer ties with Iran because of an economic blockade imposed by neighbours Azerbaijan and traditional foe Turkey.

Construction is to begin this year on a pipeline to deliver petrol and diesel fuel from Iran to Armenia, and the two countries also agreed this year to build a 470-kilometre (290-mile) rail link.

The Islamic republic is home to hundreds of thousands of Armenians and a string of historically important churches of the country's Gregorian rite.

Washington has raised concerns about Armenia's warming ties with Iran, with US officials saying in June that the country should join in international sanctions aimed at persuading Iran to halt sensitive nuclear work.

WASHINGTON (AFP) — The US government on Wednesday expressed its sympathy for relatives of the 168 people who were killed when their Caspian Airlines flight crashed in Iran earlier in the day.

Washington "extends it condolences to the families of those who lost their lives in today's crash," read a brief statement by State Department spokesman Ian Kelly.

"We are working through the US embassy in Yerevan and the Swiss Protecting Power in Iran to determine whether any American citizens were on board," the statement said.

The United States does not have diplomatic ties with Iran. Its interests are represented by Swiss diplomats in Tehran.

Witnesses and Iranian state media said the plane was ablaze before smashing into the ground and exploding near a village northeast of Tehran, shortly after taking off from the capital's international airport.

At Yerevan's airport, one woman wept as she said her sister and two nephews, aged six and 11, had been on the flight.

"What will I do without them?" said Tina Karapetian, 45, before collapsing.

It was the third deadly crash of a Tupolev Tu-154 in Iran since 2002.

The BBC's Jon Leyne says Iran's civil and military air fleets are made up of elderly aircraft, in poor condition due to their age and lack of maintenance.

Since the Islamic revolution of 1979, trade embargoes by Western nations have forced Iran to buy mainly Russian-built planes to supplement an existing fleet of Boeings and other American and European models.

TEHRAN — A technical problem is believed to have caused the crash of an Iranian airliner which burst into flames and plunged into farmland, killing all 168 people on board, a top official said on Thursday.

"The pilot could probably not be blamed for this crash and we think it was likely due to a technical problem," Ahmad Majidi, head of the transport ministry's crisis unit, was quoted as saying by the Mehr news agency.

Iranian officials said three black boxes from the Russian-built Tupolev airliner have also been found, but that two were seriously damaged.

"Because of the severity of the accident two systems linked with the black box have been damaged in such a way that the tapes have come out of the boxes and scattered on the ground," Majidi said.

The plane caught fire in mid-air en route to Armenia and plunged into farmland outside a village in northwest Iran on Wednesday just 16 minutes after take-off, killing all 153 passengers and 15 crew members.

A memorial service was due to be held at the crash site Thursday afternoon, with several MPs, local officials and Armenian leaders in Iran including the archbishop offering condolences to the victims' families, Mehr said.

Five Russian experts are due in Tehran on Friday to probe the cause of the crash of the Caspian Airlines Tupolev-154, news agencies reported.

The plane had undergone a safety check in Russia last month and received a flight licence until 2010, Majidi said.

Witnesses said the plane was ablaze before it smashed into the ground and exploded near the city of Qazvin. Television images showed a vast smoking crater littered with debris of plane parts, shoes and clothes.

"There is not a single piece which can be identified. There is not a single finger of anybody left," one relief worker told an AFP reporter at the site.

The head of the Qazvin disaster management centre, Mohammad Ali Ahani, said the remains of the victims had been transferred to Tehran.

"The families of the victims can inquire about their lost ones at the Tehran coroner's office, but it is impossible to identify the victims," he told Mehr news agency.

In Yerevan, the deputy head of the Armenian civil aviation organisation, Arsen Pogossian, said the pilot had attempted an emergency landing after an engine caught fire.

He said 147 passengers were Iranian, of whom 31 were of Armenian origin, four were Armenians and two Georgians.

Iranian officials said 10 members of the junior national judo team were also among those killed.

In Sydney, officials said an Australian brother and sister, aged in their 20s, who possibly had dual nationality, were among the dead.

The Islamic republic is home to at least 100,000 Armenians and a string of historically important churches of the country's Gregorian rite.

Witnesses spoke of seeing the plane on fire before it plunged to earth.

"I saw the plane when it was just ... above the ground. Its wheels were out and there was fire blazing from the lower parts," witness Ablolfazl Idaji told Fars news agency.

"It seemed the pilot was trying to land and moments later the plane hit the ground and broke into pieces that were scattered far and wide."

Many relatives vented their anger at Caspian Airlines, saying its planes could not be trusted.

"I hate these planes. With so much travel between Iran and Armenia, there have to be better planes," said Alex, 24, an Iranian of Armenian origin who lost around a dozen friends and relatives in the crash, including children.

The plane is a Soviet-designed medium-range three-engine aircraft and was a best-seller for the Russian aircraft industry between 1972 and 1994.

Iran, which has been under years of international sanctions hampering its ability to buy modern Boeing or Airbus planes, has suffered a number of aviation disasters over the past decade.

Its civil and military fleet is made up of ancient aircraft in very poor condition due to their age and lack of maintenance.

In the most deadly previous crash, 117 people on board another Tupolev were killed when it crashed into snow-covered mountains in western Iran in 2002.

TEHRAN, Iran — Investigators have recovered two of the three black boxes belonging to a Russian-made jetliner that crashed shortly after taking off from Tehran, Iran's state radio reported Thursday.

All 168 people aboard the Caspian Airlines aircraft bound for Yerevan, Armenia, on Wednesday were killed. The radio's report quoted chief investigator Ahmad Majidi as saying one of the two recovered boxes was damaged. It said the boxes — the plane's cockpit voice and flight data recorders — would likely be sent to the aircraft's Russian manufacturers for analysis.

The search for the third black box was continuing, Majidi said.

Bodies of the victims would be taken to Tehran later Thursday for identification, he added.

Most of the passengers were Iranians, many of them from Iran's large ethnic Armenian community, as well as 11 members of Iran's national youth judo team. Five Armenian citizens were among the dead, Armenia's Foreign Ministry said in a statement, along with two Georgians, including a staffer from the Caucasus nation's embassy in Yerevan.

Armenia on Thursday announced a one-day national state of mourning to mark the death of its citizens in the crash, according to the Russian news agency ITAR-Tass.

Reporting from Yerevan, the agency said flags would fly at half-mast on government buildings and Armenian embassies abroad. Local radio and TV have canceled entertainment programs in a show of respect, it said.

The crash was the latest in a string of air disasters in recent years that have highlighted Iran's difficulties in maintaining its aging fleet of planes.

Iranian airlines, including state-run ones, are chronically strapped for cash, and maintenance has suffered, experts say. U.S. sanctions prevent Iran from updating their 30-year-old American aircraft and make it difficult to get European spare parts or planes. The country has come to rely on Russian aircraft, many of them Soviet-era planes that are harder to get parts for since the Soviet Union's fall.

Witnesses said the plane's tail was on fire before it went down, plowing a deep, long trench into agricultural fields outside the village of Jannat Abad, and the aircraft was blasted to bits.

Flaming wreckage, body parts and personal items were strewn over a 200-yard (meter) area. Firefighters put out blazes from the crash, but smoke smoldered from the pit for hours after as emergency workers searched for data recorders and other clues to the cause.

Ali Akbar Hashemi, a 23-year-old, was laying gas pipes in a house by the field when he saw the stricken jet overhead. He said the plane was circling in the air, flames shooting from its tail section.

"Then, I saw the plane crashing nose-down. It hit the ground causing a big explosion. The impact shook the ground like an earthquake," Hashemi told The Associated Press by phone.

The Tu-154M jet had taken off from Tehran's Imam Khomeini International Airport. It crashed at 11:30 am, about 16 minutes after takeoff, outside Jannat Abad, near the city of Qazvin, around 75 miles northwest of Tehran, civil aviation spokesman Reza Jafarzadeh told state media.

At Yerevan's airport, Tina Karapetian, 45, sobbed and said she had been waiting for her sister and the sister's 6- and 11-year-old sons, who were due on the flight.

"What will I do without them?" she cried before collapsing to the floor.

The cause of the crash was not immediately known.

Serob Karapetian, the chief of Yerevan airport's aviation security service, said the plane may have attempted an emergency landing, but reports that it caught fire in the air were "only one version." He did not elaborate. A police officer told Iran's semi-official ISNA news agency that several witnesses reported seeing the plane's tail on fire.

The Tupolev's three engines are in its tail section. The flames there could indicate "an uncontained engine failure," said Patrick Smith, a pilot and the air travel and safety writer for Salon.com.

But he said it's too early to tell. The crash's root cause could be elsewhere, and the flames a sign of a compressor stall caused when the plane went out of control, interrupting airflow through the engine, Smith said.

The crash is Iran's worst since February 2003, when a Russian-made Ilyushin 76 carrying members of the elite Revolutionary Guards crashed in the mountains of southeastern Iran, killing 302 people aboard. That crash was a sign of how maintenance problems have also affected Iran's military.

Caspian Airlines is an Iranian-Russian private joint venture founded in 1993, with a fleet of Tu-154s built between 1989 and 1993. Russia produced 900 Tu-154s until production was halted in 1996.

The plane, which was flying from the Iranian capital to Yerevan in Armenia, crashed 16 minutes after take-off from Tehran's Imam Khomeini International Airport.

Witnesses said the 22-year-old Tu-154, which had 153 passengers and 15 crew, nose-dived from the sky with its tail on fire.

Wreckage was scattered over a large area.

On Thursday, state television said the cause of the crash was still unknown.

But Mr Majidi was quoted by the semi-official Mehr news agency as saying that the pilot was experienced and the crash was "likely due to technical problems".

He added that the flight data recorders, or "black boxes", might be sent to Russia for analysis.

"Because of the severity of the crash, the two black box recorders found are badly damaged, even though they are made of steel," Mr Majidi said.

"The tapes were out on the ground. We might send the black box to the country where it was manufactured [Russia] to chase the issue with their help."

Most of those on board the flight were Iranian, though there were also some Armenian and Georgian citizens.

Mr Majidi said DNA testing would be needed to identify the remains.

Friends and relatives of the victims gathered at the crash site for a religious ceremony on Thursday, throwing flowers into the crater created when the plane hit the ground.

Archbishop Sebo Sarkissian of Iran's Armenian community was among those to take part.

It was the third deadly crash of a Tupolev Tu-154 in Iran since 2002.

Correspondents say Iran's civil and military air fleets are made up of elderly aircraft, in poor condition due to their age and lack of maintenance.

Since the Islamic revolution of 1979, trade embargoes by Western nations have forced Iran to buy mainly Russian-built planes to supplement an existing fleet of Boeings and other American and European models.

TEHRAN, Iran — Investigators have recovered the three black boxes belonging to a Russian-made jetliner that crashed in northwest Iran shortly after taking off from the capital, killing all 168 on board, authorities said Thursday.

Remains of the dead — many badly burned and damaged — were brought to Tehran for identification, as relatives from Armenia, the passenger jet's destination, headed for Iran to retrieve their loved ones' bodies.

Khristofor Sogomonian, whose father was among those killed, said he would "try to find anything and to commit his body to the soil."

Diana Sarkisian told The Associated Press at the airport in Armenia's capital Yerevan, that her cousin was aboard the plane as the first leg of a trip to her husband in the United States. "I had hoped that she was alive, but now all doubts have fallen away," said Sarkisian, an Iranian national.

The black boxes — containing the plane's cockpit voice and flight data recorders — will be key to determining the cause of the crash, which remains unknown. Witnesses said the plane's tail, where the engines are located, was on fire before it went down nose first, plowing a long trench into agricultural fields outside the village of Jannat Abad, and the plane was blasted to bits. Parts of the trench were up to four meters (yards) deep.

Chief investigator Ahmad Majidi said one of the recovered boxes was damaged, state radio said. The boxes would likely be sent to the aircraft's Russian manufacturers for analysis, he said.

A team of Russian air accident experts was due to arrive in Iran on Friday to help in the investigation of the latest crash, civil aviation spokesman Reza Jafarzadeh told the semi-official news agency ISNA.

Majidi initially said two black boxes were found and that investigators were searching for a third. Later state TV reported that the third was found, some 4 kilometers (2.5 miles) away from the crash. Black boxes, built to survive crashes and intense fires, record a plane's performance, like speed and altitude, as well as communications between the cockpit crew or with air traffic controllers.

The crash of the Tupolev jet leased by Caspian Airlines was the latest in a string of air disasters in recent years that have highlighted Iran's difficulties in maintaining its aging fleet of planes. Iranian airlines, including state-run ones, are chronically strapped for cash, and maintenance has suffered, experts say.

U.S. sanctions prevent Iran from updating its 30-year-old American aircraft and make it difficult to get European spare parts or planes. The country has come to rely on Russian aircraft, many of them Soviet-era planes that are harder to get parts for since the Soviet Union's fall.

Iranian civil aviation agency chief Ali Ilkhani said the Tu-154M that crashed was built in 1987, was bought by Iran in 1998 and had an overhaul certificate valid until 2010, state TV said.

Most of the passengers were Iranians, including 42 from Iran's large ethnic Armenian community, as well as 11 members of Iran's national youth judo team.

Five Armenian citizens were among the dead, Armenia's Foreign Ministry said in a statement, along with two Georgians, including a staffer from the Caucasus nation's embassy in Yerevan.

Armenia on Thursday announced a one-day national state of mourning to mark the death of its citizens in the crash. Flags were flying at half-mast on government buildings and Armenian embassies abroad. Local radio and TV have canceled entertainment programs in a show of respect.

Iran's national airline sent a Boeing 747 to Yerevan Thursday to help take victims' relatives to Tehran. Caspian Airlines' representative in Armenia, Arlen Davudian, said victims' relatives would be provided hotel rooms and transportation to the crash site.

Victims' relatives, he added, would be paid compensation of at least euro32,000 ($45,216).

At the site of the crash on Wednesday, flaming wreckage, body parts and personal items were strewn over a 200-yard (meter) area. Firefighters put out blazes from the crash, but smoke smoldered from the pit for hours after as emergency workers searched for the data recorders and other clues to the cause.

The Tu-154M jet had taken off from Tehran's Imam Khomeini International Airport. It crashed at 11:30 am, about 16 minutes after takeoff, outside Jannat Abad, near the city of Qazvin, around 75 miles northwest of Tehran.

The crash is Iran's worst since February 2003, when a Russian-made Ilyushin 76 carrying members of the elite Revolutionary Guards crashed in the mountains of southeastern Iran, killing 302 people aboard. That crash was a sign of how maintenance problems have also affected Iran's military.

Caspian Airlines is an Iranian-Russian private joint venture founded in 1993.